Shreve A P, Trautman J K, Frank H A, Owens T G, Albrecht A C
Department of Chemistry, Cornell University, Ithaca, NY 14853.
Biochim Biophys Acta. 1991 Jun 17;1058(2):280-8. doi: 10.1016/s0005-2728(05)80248-8.
The B800-to-B850 energy transfer time in the purified B800-850 light-harvesting complex of Rhodobacter sphaeroides 2.4.1 is determined to be 0.7 ps at room temperature. The electronic state dynamics of the principal carotenoid of this species, spheroidene, are examined, both in vivo and in vitro, by direct femtosecond time-resolved experiments and by fluorescence emission yield studies. Evidence is presented which suggests that carotenoid-to-bacteriochlorophyll energy transfer may occur directly from the initially excited carotenoid S2 state, as well as from the carotenoid S1 state. Further support for this conjecture is obtained from calculations of energy transfer rates from the carotenoid S2 state. Previous measurements of in vivo carotenoid and B800 dynamics are discussed in light of the new results, and currently unresolved issues are described.
在室温下，球形红杆菌2.4.1纯化的B800 - 850捕光复合物中从B800到B850的能量转移时间被确定为0.7皮秒。通过直接飞秒时间分辨实验和荧光发射产率研究，在体内和体外研究了该物种主要类胡萝卜素——球形烯的电子态动力学。有证据表明，类胡萝卜素到细菌叶绿素的能量转移可能直接从最初激发的类胡萝卜素S2态以及类胡萝卜素S1态发生。从类胡萝卜素S2态能量转移速率的计算中获得了对这一推测的进一步支持。根据新结果讨论了之前对体内类胡萝卜素和B800动力学的测量，并描述了目前尚未解决的问题。
